A hot-box test facility was fabricated by Wiss, Janney, Elstner and Associates for Jim Walter Research Corp. The equipment is capable of operating in either a calibrated or a guarded mode. When operating in the guarded hot-box mode, the equipment is in accordance with the ASTM Test for Thermal Conductance and Transmission of Built-Up Sections by Means of the Guarded Hot Box (C 236-66). When operating in the calibrated hot-box mode, the equipment is in accordance with the proposed ASTM Test for Thermal Performance of Building Assemblies by Means of a Calibrated Hot Box, which is presently being written by ASTM Subcommittee C16.30 and for which input has been provided from this facility. The basic design consists of a separate cold box, hot box, specimen frames, refrigeration unit, control and data-acquisition panel, and metered box. Both the hot and cold boxes are insulated with low-density polyurethane foam, with an overall minimum thickness of 30.5 cm (12 in.). The attitude of the test facility can be varied to provide upward, downward, or horizontal heat flow. Both the hot and cold boxes can provide variable air velocities parallel to the specimen face.

The following is a summary of the operating characteristics of the test facility: